On the storage stability of CaO biodiesel catalyst. Hydration and carbonation poisoning

Lime based catalysts are reported to be active in oil alcoholysis, biodiesel production, but their sensitivity to moisture and atmospheric CO2 can hinder their use at the industrial level because it is suspected that they must be manipulated in a controlled atmosphere. The storage stability of lime catalyst was investigated for 180 days (temperature in the range 20-38 degrees C, relative humidity higher than 40%). Catalytic data showed biodiesel yields ranging from 87.5%, for the first day, to 79.4% for the 180th day, passing through a maximum of 91.5% obtained in the 30th day of storage. Hydration was mainly a surface process since the Ca(OH)(2) bulk phase was detected only at the end of the storage period. A catalyst stored for 10 mounts was successfully reactivated by annealing at 470 degrees C thus proving that CaO material is stable enough during storage and handling to be used as a biodiesel catalyst.

Automated summary

Lime based catalysts are active in oil alcoholysis and biodiesel production, but their sensitivity to moisture and CO2 may hinder industrial applications. After 180 days of storage, it was found that the biodiesel yield of lime catalysts decreased with time, with a peak yield reached on day 30. Additionally, the stability of CaO material during storage and handling was demonstrated by successful reactivation through annealing at 470 degrees C.